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2 Sheets-Sheet 1.

Patented Oct. 23, 1888.

E. S. BOYNTON. MEANS FR SEGURING PRINTING PLATES T0 BEDS 0R CYLINDBRS0I' PRINTING MACHINES.

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(No Model.)

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2 Sheets-.Sheet 2.

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E. S. BOYNTON. MEANS EOE SEGUEING PRINTING PLATES To EEES 0E GYLINDEES0E PRINTING MACHINES.

Patented Oct. 23. 1888.

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EDWARD S. BOYNTON, CF NEW YORK, N. Y., ASSIGNOR TO THE CAMPBELL PRINTINGPRESS AND MANUFACTURING COMPANY, OF SAME PLACE.

MEANS FOR SECURING PRINTING-PLATES T BEDS 0R CYLINDERS 0FPRINTlNG-IVlACHINES.

SPECIFICATION forming part of Letters Patent No. 391,733, dated October23, 1888.

Application led January 25, 1888.

To all whom it 'may concern:

Be it known that I, EDWARD S. BoYNToN, of the city of New York, in thecounty and State of New York, have invented a new and useful Improvementin Means for Securing Printing- Plates to Beds or Cyiinders ofPrinting-Machines, which invention is fully set forth and illustrated inthe following specification and accompanying drawings.

The object of this invention is to provide means for readily securingplates of zinc, calcisinterj or similar or Vother thin plates to thebeds of reciprocating or to. the printingcylinders of rotary printingmachines, by which such plates may be quickly removed or exchanged andalways brought under an equalized strain, thus insuring that the platesshall lie close to the bed or cylinder surface without buckling ordistortion, or danger ofbeing torn out, or having their edges marred. Itis also the object to so secure such plates that they shall entirelycover the beds at the ends where the impressioncylinder enters upon andleaves the plate used, while at the same time excluding the water usedin printing from such plates from entering between the plate and the bedto which it is secured, and to also offer a smooth beveled or roundedsurface for the impression cylinder to enter upon and leave similar tothe rounded edges given to lithographicstonesin power lithographieprinting.

The invention will irst be described in detail, and then particularlyset forth in the claim.

In the accompanying drawings, Figure l shows a longitudinal verticalsection through a dat bed and plate, taken at the line X X of Fig. 2;and Fig. 2 is a View in plan of Fig. l, With a portion of the plate andbed. broken away to show the mechanism of the straininglevers. Figs. 3and et are similar views of a cylindrical-surfaced bed or turtle.

In said figures the several parts are indicated by numbers, as follows:

The number l in Figs. l and 2 indicates an auxiliary bed-piece, takingthe place in a reciprocating lithographie press of the ordinarylithographie stone, and in Figs. 3 and Ll the Same number indicates acylindrical-surfaced Serial No. 261,855. (No model.)

turtle or plate-holder as used in rotary machines, said bed-piece andplate-holder being each provided with recesses 2,cast in one edge,through which recesses are passed the free ends of a series of levers,3.A Upon the other edge of the bed l is secured a strip of metal, 4,rabbeted at its lower edge so as to leave or form a narrow slot or spacebetween it and the bed l. The lower edge of the strip 4 is rounded toavoid any sharp-cornered bend in the thin plate 5. Two ofthe othercorners of the bed l are also rounded sufciently to allowsaid thin plateto be drawn easily over them,| as at 6 and 7. A rod 8, is secured in thevertical webs of the bed l, and the series of levers 3, above mentioned,are loosely journaled upon said rod. Near the free ends of the levers 3are set screws 9, impinging upon the under side of the surface web ofthe bed for the purpose of depressing the free ends of the-levers 3.Said free ends are T-shaped and are secured to a rabbeted strip l0exactly similar to strip 4 and forming a groove between the l"-heads oflevers 3 and the striplO.

In adjusting the printing-plate it is first turned in a U shape at twoof its edges, as shown, and then bent into form proper to pass over therounded edges of the bed 1. It is then slid endwise into the groovesformed by the rabbeted strips 4 and l0, and by the manipulation oftheset-screws 9 put under even strain until the whole plate lies iat uponthe surface of the bed. The grooves formed by the rabbeted strips 4. andl0 need not be nearly a close lit to the thickness of the plate 5, as itis found in practice that if the curves made at the points ll and l2 inthe plate 5 be small the grooves may be fully double the thickness ofthe plate without danger of the plates pulling out; and thus, having aloose lit iu the grooves, the plate may be readily slid on or off thebed, as hereinbefore explained.

Having thus fully described my said improvement as of my invention, Iclaim- The above-described means for holding thin plates upon theprinting beds or cylinders of printing-machines, consisting of arabbeted plate, as 4, forming a thin groove opening downward at one edgeof the bed, andaseries of adjustable levers, as 3, provided with adyplaced under equalized strain and capable of justingscrews, as 9, andcarrying on their free being quickly removed or exchanged, subro ends asimilar vertical groove at the opposite stantia-lly as set forth.

end ofthe bed, in combination with said bed 5 provided with roundededges, as 6 and 7, EDW ARD S' BOYNTON' whereby said plates are securedby their Witnesses: curved edges in intimate Contact with the FRANCIS P.REILLY, printing bed or Cylinder at all points and JOHN TULLY.

